I. Field of the Invention
The present invention relates to wellbore cleaning tools, and more particularly, to a jet-biased wellbore cleaning tool which biases downhole the brushes and/or scrapers of the tool toward the casing wall with fluid jets.
II. General Background
Cleaning tools using brushes and scrapers are well known. While casing sizes are standard, during brushing, the bristles of the brushes bend and distort, as the tool engages debris adhering to the casing. Hence, during the cleaning action, the ability of the brush or scraper to apply a force of abrasion diminishes over time. Thus, the tool must be removed from the wellbore and the brushes or scrapers removed. Then, the tool is reinserted downhole which completes a roundtrip.
Removing the cleaning tool to replace brushes or scrapers is time consuming and costs the oil field industry revenue. Thus, limiting the downhole roundtrips by the cleaning tool and maintaining the tools ability to clean is highly desirable. Sometimes, different sized cleaning tools are needed as the diameter of the wellbore varies.
Known cleaning tools do not control the abrasion force applied to the debris on the casing wall or the casing wall. Instead, a brush or scraper when engaging debris causes the cleaning tool to reciprocate in the casing. Thus, the total force of abrasion can be reduced by the amount the cleaning tool moves away from the casing wall or debris as debris is encountered.
In view of the foregoing, there is a continuing need for a cleaning tool with casing abrasion cleaning members and fluid jets wherein the fluid jets are arranged to provide a force of fluid to carry debris to the top of the wellhead and, simultaneously and automatically, bias the casing abrasion cleaning members in the direction of the casing wall.
There is a continuing need for a cleaning tool which can rapidly remove and replace the casing abrasion cleaning members during operations.
There is a continuing need for a cleaning tool which is constructed and arranged to automatically force the casing abrasion cleaning members to make direct contact with debris on the casing wall or the casing wall and minimize reciprocation by the cleaning tool.
There is a need for a cleaning tool which enhances the force of abrasion applied to the debris on the casing wall and extends the force of abrasion on the casing wall for longer periods of time than existing cleaning tools.